In recent years, a persistent organic pollutant, namely perfluorooctanoic acid (PFOA), that widely exists in the environment, has attracted extensive attention. The efficient treatment of PFOA has always been a research hotspot and challenging subject. Due to its eco-friendly, high-efficiency, low-cost and completely degradable features, photocatalytic degradation technology has become an effective method for promising application in the treatment of PFOA, as compared with other methods. The key point of photocatalytic technology is to construct photocatalytic semiconductor materials that can make efficient use of optical energy, while semiconductor materials are often limited by fast recombination rate of photogenerated electron-hole pairs. At present, researchers often modify semiconductor materials by means of metal ion doping, precious metal deposition, carbon material composite, construction of heterojunction, variation of microscopic morphology and so on to improve photocatalytic degradation capability. According to the current research status at home and abroad, this paper introduces the advantages of photocatalytic technology in the degradation of PFOA, summarizes the photocatalytic oxidation degradation mechanism and the research progress of photocatalytic treatment of PFOA by semiconductor materials. Combined with the advantages, disadvantages and efficiency comparison of different semiconductor catalytic materials, the shortcomings of photocatalytic treatment of PFOA are discussed. This paper provides reference and theoretical support for further development and application of photocatalytic technology in the degradation of PFOA.

Studying the resilience of forest ecosystems at the provincial scale in China and quantifying the impact of each index weight on resilience could provide a decision-making foundation for sustainable forest management at the macroscale. This paper constructed a provincial-scale forest ecological resilience evaluation index system based on the ecological pressure-state-response model from the two aspects of vulnerability and adaptive capacity and adopted the OAT (one-at-a-time) method to quantify the weight of each index's impact on the assessment results of forest ecosystem resilience. The results show that the average values of the vulnerability, adaptive capacity and resilience index of the forest ecosystem were 0.309, 0.323 and 0.320, respectively; the impact of forest ecosystem response capacity on forest ecosystem resilience was higher than that of forest ecosystem vulnerability, with coefficients of 0.720 and 0.280, respectively. Accumulation per unit area, the control rate of rodent damage and the restoration area of degraded forests were the most sensitive factors to forest ecosystem resilience, while fire prevention investment, the area of closed hills for afforestation and investment in forest management were less sensitive. Overall, the resilience level of the provincial forest ecosystem was relatively low, and the evaluation results of forest ecosystem resilience were generally and relatively stable, which indicates that the weights initially determined by the entropy method are reasonable.

In recent years, the coordination of rapid urbanization has become an important factor that may restrict urban development. This study selected the night lighting data and socio-economic data of 72 county-level administration units in Jiangsu Province in 2015 and 2019. The spatial autocorrelation model and quaternary coordination model were selected to analyze the spatial agglomeration status of urban population, GDP, night lights, and construction land, which revealed the coordination status of urban expansion in Jiangsu Province. The results show that:(1) Urban population, secondary and tertiary industries, construction land and night lights showed obvious spatial agglomeration characteristics, and the main agglomeration area is in southern Jiangsu; (2) Land urbanization was faster than population urbanization in 90% of the area of Jiangsu Province, only 10% of the area with land urbanization slower than population urbanization. Meanwhile, about 30% of the regional land urbanization was faster than the economic growth, and about 70% of the regional land urbanization was slower than the economic growth. (3) From the perspective of the coordination degree of economy, population, night lighting and construction land, 95% of the regions were in the coordinated development in 2015 and 2019. Comparing these two periods, 40% of the regional coordination degree of Jiangsu Province was increasing, and the remaining 60% was decreasing. These results can provide optimized ideas for urban expansion of Jiangsu Province in the future, promote the healthy, coordinated and sustainable development of the region, and provide references for coordinated urban expansion in other provinces.

The optimization of lakeside villages is an important aspect of the coordination between protection and development of land spaces in the basins of big lakes. Taking the first-level protection area of the Chaohu Lake Basin as the study area and on the basis of geospatial analysis technology, the study comprehensively used the data including the land survey, national geographical survey, high resolution land use (5 m) and topographic terrain survey to reveal the water environment capacity dominated influencing factors and external driving mechanism of villages patterns, and the optimization direction and regulation of villages patterns are proposed. The results show that the village pattern in the first-level protection area was characterized by land fragmentation, rural community hollow and decentralization. The above characteristics clarified from the viewpoint of differences in land use, population and spatial pattern. The total area of villages land is 2 598.4 hm², and the average size of patches is about 2.4 hm², and the total population is about 1.39 million. The above village pattern had a driving-constraint relationship among external factors including ecological sensitivity, disaster prevention, development agglomeration and cultural protection. The main constraints were from the ecologically sensitive areas such as the embankment area and other forest & grass areas which accounted about 29.1% of the total area. The first-level protection area actually has terrain conditions suitable for village development. There are still 50% villages located in flooded area, and 60% villages in urban fringe area with 1-kilometer buffer. Thus, four types of village pattern optimization of separating, shrinking, controlling and expanding are proposed. The results of the study provide cognitive ideas and technical support for the territory land plan in the lakeside zone in the big lake regions.

As a typical ecological agriculture technology, the rice-shrimp co-cultivation technology is an important way to alleviate the deterioration of the ecological environment and ensure the sustainable development of agriculture. The item response theory (IRT) model was further used to measure the information acquisition capacity. On this basis, the Heckman model was further used to analyze the impact of social interaction and information acquisition capacity on farmers' adoption of the rice-shrimp co-cultivation technology by using 878 survey data in the Yangtze River Basin. And the mediating effect of the ability to obtain information was further discussed. The results show that:(1) The more channels that farmers used, the stronger their ability to obtain information. In the same number of channel combinations, the channels with higher discrimination could lead to higher information acquisition capabilities.(2) Social interaction, reciprocity and social norms could all encourage farmers to adopt rice and shrimp co-cultivation technology. Reciprocity also had a positive impact on the degree of adoption. (3) Information acquisition capacity had a positive effect on the decision-making and the degree of adoption of farmers' rice-shrimp co-cultivation technology. Social interaction can promote the adoption and decision-making of farmers through the ability to obtain information. While the reciprocity can be achieved through the ability to obtain information which could have an impact on the degree of adoption of the technology by the farmers. Therefore, it is necessary to build a multi-level technical information channel system, broaden the information network of farmers, establish a rural exchange platform to carry out rich rural cultural activities, and enhance the interaction of farmers and form emotional exchanges, and promote the normal operation of the "pay-reward" virtuous cycle system.

Order Galliformes is one of the most threatened animal taxa worldwide. Despite the harsh environment and climate conditions, the alpine ecosystems of Hengduan Mountains support rich diversity of Galliformes. Understanding the spatio-temporal dynamics of Galliformes in the alpine ecosystems and species' habitat selection is crucial for effective conservation. In this study, 109 infrared cameras were positioned at altitude from 3 500 m to 4 800 m, covering 72 grids (1 km×1 km) to monitor alpine Galliformes species in Wolong National Nature Reserve, Sichuan Province from May of 2019 to January of 2021. The monitoring involved effort of a total of 33 759 trap days. The results show that:(1) There were 9 Galliform species in alpine ecosystems, with high proportion of endemic and protected species, and Chinese monal (Lophophorus lhuysii), snow partridge (Lerwa lerwa) and blood pheasant (Ithaginis cruentus) dominated this community with higher relative abundances. (2) Both species richness and relative abundance of alpine Galliformes were greater in shrubs with the altitudinal range from 3 500 m to 4 000 m, while relative abundance of all the species were much higher during breeding seasons (from April to July) than during non-breeding seasons (from August to March). (3) Snow partridge select preferentially habitats at upper slopes, blood pheasant prefer shrubs with lower altitudes and avoided tundra, and Tibetan snowcock (Tetraogallus tibetanus) prefer higher altitude and tundra habitats while avoiding shrubs, while Chinese monal have no significant habitat preference. (4) Species richness and relative abundance were the highest in the monitored grids in Tizigou and Yinchanggou, indicating these areas are important areas for Galliformes species' distribution throughout the Wolong National Nature Reserve. Given remarkable conservation value of alpine Galliformes in Wolong National Nature Reserve. It is advised that:(1) to consider Chinese monal as a key conservation species in alpine ecosystems and focus on the protective management of shrubs at an elevation of 3 500-4 000 m, (2) to treat Tizigou and Yinchanggou as priority areas for regional Galliformes conservation.

Birds are highly dependent on food and habitat in urban landscape, and environmental factors are closely related to urban birds. However, the effect of land cover patterns on bird communities in urban areas remains unclear. From January to October, 2019, fixed line transect method was used to investigate the relationship between urban bird diversity and land cover in Lishui District, Nanjing, China. The results show that there were significant differences in the number and diversity index of bird species among seasons. The individual numbers of birds in spring and autumn were significantly larger than that in winter. The diversity indices in spring, summer and autumn were larger than that in winter, and the evenness index in spring was greater than that in winter. No significant difference was found in the number of individuals among seasons. The species richness was positively correlated with the proportion of farmland area, forest area and the landscape diversity index. The number of individuals was negatively correlated with the proportion of grassland area, and positively with the landscape diversity index. The diversity index was positively correlated with the proportion of farmland area. During spring, summer and winter, the individual numbers of omnivorous, carnivorous and granivorous birds were positively correlated with the proportion of grassland area, while the numbers of insectivorous and frugivorous birds were positively correlated with the proportion of forest area. The numbers of omnivorous, carnivorous and granivorous birds were positively correlated with landscape diversity index in spring and summer. The number of omnivorous birds was positively correlated with the proportion of construction land area in winter. The individual number in bird feeding guilds and the land cover pattern in autumn showed no significant correlations. In order to increase the number of bird individuals and species, it is suggested to increase the diversity of land cover pattern, and the proportion of woodland area, and to enrich the environmental heterogeneity of grassland in urban planning and management.

Solar radiation, relative humidity, and ambient temperature are three key meteorological controlling factors for the photochemical reaction of ground-level ozone (O₃). Their distribution forms play an extremely important role in the nonlinear evolution of O₃. The hourly O₃ concentration data and corresponding meteorological data in the same period from 2016 to 2019 during summer in Chengdu were collected and Maximum Likelihood Estimation method was used to estimate parameters for probability distribution functions. At the same time, Kolmogorov-Smirnov test statistics (K-S test), root-mean-square-error (RMSE), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) were further combined to analyze the goodness of fit of multiple probability distribution functions of the three meteorological controlling factors for O₃ photochemical reaction,respectively. The results indicate that:(1) Johnson SB distribution function had the best fitting effect for both solar radiation and relative humidity. Additionally, under different O₃ concentration levels, the probability distribution of solar radiation and relative humidity kept obey Johnson SB distribution at significant level of α=0.05 in K-S test. (2) However, Johnson SU distribution function had the best fitting effect for ambient temperature. Moreover, the probability distributions of ambient temperature obey Johnson SU distribution under different O₃ concentration levels at significant level of α=0.05 in K-S test. (3) The probability distribution characteristics of the three meteorological controlling factors vary significantly and regularly with the changing of O₃ concentration level. These research results mentioned above could provide technical supports for the construction of O₃ pollution potential model during summer in Chengdu.

A device with the filtration and degradation zone, based on the principle of constructed wetland and ecological filter bed, was designed to construct artificial ecosystem at hard revetment area to restore the polluted aquatic environment. The short-term and long-term effects of the setting of filtration and degradation zones with plants and no plants on the concentration of water pollutants (TN, TP, and TOC) were studied, and the Biolog method was used to analyze the functional diversity of water microorganism. The results showed that, short-term setting of the filtration and degradation zones had no effects on the concentrations of water pollutants, while the long-term setting of filtration and degradation zone significantly reduced the concentration of pollutants. Compared with control, the ρ(TN), ρ(TP) and ρ(TOC) in the water with the filtration and degradation zones with no plant decreased by 17.2%, 16.6% and 29.8%, respectively, while the setting of filtration and degradation zones with plants decreased the concentrations of water pollutants by 28.7% (TN), 18.4% (TP) and 42.7% (TOC), respectively, during the nine months of the experiment. Long-term setting of the filtration and degradation zones increased the carbon source utilization and function diversity of water microorganism, optimized the types of water microbial carbon source utilization. As compared with the filtration and degradation zone without plant, the filtration and degradation zone with plants showed more obvious effects on the improvement of microbial functional diversity in water. The results indicated that the setting of the filtration and degradation zones can partially solve the aquatic ecosystem degradation caused by the hardening of the river and lake shore, and could be important guiding significance for improving ecological function of hard revetment area.

There is a coupling of sulfur cycle with denitrification (DN) and dissimilatory nitrate reduction to ammonium (DNRA) in the sediment-water system. The effects of reduced sulfur on DN and DNRA were revealed by sequentially adding 0 (Group N), 50 (Group L) and 75 mg·L^-1 (Group H) reduced sulfur to the constructed sediment-water microcosm systems, and then the concentration changes of various forms of nitrogen in overlying water, pore water and sediment as well as microbial community structure were analyzed. Results show that 38.02% and 33.27% of reduced sulfur were converted into SO₄^2-, respectively, when the dosage of reduced sulfur was 50 and 75 mg·L^-1. Sulfur oxidation promoted the occurrence of DN, and caused the total nitrogen of Group L and Group H decrease by 11% and 8%, respectively, compared with Group N, but had no significant effect on the process of DNRA. In addition, the sum of relative abundances of genera Thiobacillus and Dechloromonas functioned with sulfur autotrophic denitrification increased with concentration of reduced sulfur, and occupied 5.69%, 6.52%, 8.70% in Group N, L and H, respectively. In contrast, the relative abundance of heterotrophic nitrate reducing bacteria (HNRB) was only 0.98%, 0.91%, and 1.05% in Group N, L and H, respectively, and the DNRA bacteria (with the relative abundance no more than 1%) were unaffected by reduced sulfur. Such results further confirmed that the nitrate reduction process in the system was dominated by sulfur autotrophic denitrification.

In order to prepare an effective adsorbent to remediate arsenic pollution, ferrihydrite@biochar composite materials (Fh@BC) were synthesized using ferrihydrite (Fh) and peanut shell biochar (BC) as raw materials. The property of the composite material for adsorption of arsenic was explored. Then, the adsorbent was characterized by SEM-EDS, BET, XRD, FTIR and XPS. Additionally, the simplified sequential leaching was used to analyze the speciation of adsorbed arsenic and evaluate the stability of arsenic adsorption process. The results show that the ferrihydrite was successfully loaded on biochar, the total pore volume and specific surface area of the composite material was effectively improved compared to pure ferrihydrite. Furthermore, the adsorption of arsenic by the composite material was better described by the Langmuir model and the pseudo-second-order kinetic model, and the maximum arsenic adsorption capacity of the composite material could reach to 80.09 mg·g^-1. Moreover, the composite material could adsorb arsenic in a wide pH range. The ferrihydrite particles on the surface of the composite material played an important role in the adsorption of arsenic. The mechanism of arsenic removal mainly includes electrostatic attraction and coordination complexation. In addition, the stable arsenic of the arsenic adsorbed by the composite material accounted for 99.18% of the total amount, and the risk of secondary release of pollutants was low.

To study the movement of nitrogen (N) and phosphorus (P) on a purple soil slope during rainstorm runoff, the rainfall runoff process of Lanlingxi watershed in Three Gorges Reservoir Area was monitored in 2019 using a slope plot. Two rainstorms, typical of long-term uniform rainfall (June 22) and short-term heavy rainfall (August 3), were selected to analyze the impact of rainstorm characteristics on surface flow, interflow and N and P loss with runoff. The results show that:(1) there were significant differences in runoff, runoff duration, peak flow and runoff rate between the two rainstorm events. The time of peak rainfall intensity had a decisive effect on the interflow generation time. (2) Under different rainstorm conditions, the concentration of N and P in surface flow and interflow were significantly different. This was mainly affected by rainfall and peak rainfall intensity. The concentrations of N and P in runoff were negatively correlated with rainfall in the same period, and positively correlated with runoff in the same period. (3) Total N (TN) was the main form of soil nutrient runoff loss, and there was a significant positive correlation between N and P loss and runoff loss. On June 22 and August 3, TN loss was 4.03 and 8.49 kg·hm^-2, respectively, in which the contribution rate of interflow was 88.59% and 85.51%, respectively. The total P (TP) loss was 0.11 and 0.33 kg·hm^-2, respectively, of which the loss in granular form accounted for 54.55% and 60.61%, respectively. The results show that short-duration heavy rainfall caused greater soil erosion and nutrient loss. This provides a reference for the prevention and control of agricultural non-point source pollution in the Three Gorges Reservoir Area.

Benggang is vividly called "ecological ulcer" in the south red soil area. The purpose of this study is to clarify the characteristics of rare earth elements (REEs) in collapsed hillocks (Benggang) with different soil erosion intensities in extremely degraded ecosystems and to explore the ecological restoration measures in controlling REEs migration. Taking 3 Benggang samples in Huangnikeng, Zhuotian Town, Changting County of Fujian Province representing 3 different erosion intensities (mild, intense, and extremely intense) as the study cases, the effects of different soil erosion intensities on contents characteristics and horizontal migration of REEs in Bengbang system were analyzed. The results show that the highest content of REEs in Benggang with intense erosion occurred in the gully area, while the highest content of REEs in Benggang with mild and intense erosion occurred in the colluvial area. Under the same soil erosion intensity, the REE contents in the soil of different parts of the slope of Benggang and the control slope were significantly different (P<0.05). The exchangeable and residual forms of REEs were dominant among the rare earth binding forms additionally, exchangeable REEs content in Benggang systems was significantly higher than that of non-collapsed slope. The average content of bioavailable forms in non-rhizosphere soil of Dicranopteris dichotoma was 214.90 mg·kg^-1, while in rhizosphere soil was 231.78 mg·kg^-1. The research results show that with the intensification of soil erosion in Benggang, the migration capacity of REEs to the downstream was enhanced. Therefore, the ecological restoration and management of Benggang system in the extremely degraded ecosystem should be strengthened to reduce the loss of surface soil and prevent and control horizontal migration of REEs. The ecological restoration measure of rare earth hyper-accumulated plants will be beneficial to prevent and control the REEs horizontal migration in the degraded Benggang ecosystem. Consequently, the distribution of Dicranopteris dichotoma, one of the REEs accumulation plants, showed that the available REEs can migrate from the original soil to the Dicranopteris dichotoma, which can be beneficial to control REEs migration and reduce the potential ecological risk. The results can provide a theoretical basis for expanding the ecological restoration fields of REEs control in Benggang.

The remediation of farmland soil contaminated by heavy metal is a difficult environmental issue in China. In this study, cadmium (Cd)-contaminated farmland soil from Mashigou, Songxian County of Henan Province was collected as the test soil, and five treatments, including hydrated lime, calcite, zeolite, montmorillonite and biochar, were added and assessed using an indoor culture test method. The Tessier modified sequential seven-step extraction method was used to analyze the Cd speciation content in the treated soil. The passivation effect of different treatments on Cd pollution at 1%, 3% and 5% was then assessed in weakly acidic soil. Results show that the five treatments increased the soil pH in the order of:hydrated lime (2.00-2.50 unit increase) > calcite (0.86-1.38 unit increase) > montmorillonite (0.83-1.19 unit increase) > biochar (0.07-0.38 unit increase) > zeolite (0.11-0.20 unit increase). The five treatments all reduced the content of ion exchangeable Cd in soil, but their effects were substantially different. The passivating sequence was as follows:hydrated lime > calcite > biochar > montmorillonite > zeolite. After 50 days of culture with treatments at 1%, 3% and 5%, the reductions in exchangeable Cd were 76.65%-90.66% with hydrated lime, 46.12%-53.77% with calcite, 9.36%-33.03% with biochar, 11.72%-19.14% with montmorillonite, and only 0%-10.94% with zeolite. The treatments changed the proportion of Cd forms in soil to different degrees. The proportions of weakly bound Cd (carbonate bound, humic acid bound, iron and manganese oxide bound) increased significantly, and the proportions of strongly bound Cd (strong organic bound, silicate residual state) also increased to a certain extent. In general, hydrated lime and calcite greatly reduced exchangeable Cd, biochar had an intermediate effect, and montmorillonite and zeolite had the minimal effects on exchangeable Cd. Considering the effects of these treatments on the soil pH and Cd passivation efficiency, 3% calcite is the best passivating agent for weakly acidic Cd-contaminated soil under laboratory culture test conditions. As a natural non-metallic mineral, calcite showed efficient passivation, and it is cheap, easy to obtain and environmentally friendly, suggesting its potential for in-situ remediation of weakly acidic Cd contaminated soil.

In view of the increasingly serious soil cadmium (Cd) pollution, the improper in-situ remediation technology is one of the most widely used methods based on the domestic and foreign heavy metal remediation methods. In this study, different minerals, i. e., sepiolite (BM2), montmorillonite (BM3), attapulgite (BM4), zeolite (BM5), hydroxyapatite (BM6) and quicklime (BM7), and biochar (BM1) were used as restoration materials compared with control (BM0). A two-year remediation experiment was carried out on low Cd contaminated farmland soil in Zhejiang Province. The results show that biochar, sepiolite, attapulgite, hydroxyapatite, and quicklime slightly enhanced rice yield but with no statistically significant difference. All the passivation treatments reduced soil available Cd and rice grain Cd contents. The reduction of grain Cd contents was in an order of biochar > quicklime > zeolite > montmorillonite > hydroxyapatite > attapulgite > sepiolite > control. Besides, the soil available Cd and grain Cd after quicklime addition were 0.214 and 0.169 mg·kg^-1, respectively, which were decreased by 25.17% and 41.26%, respectively compared with BM0. In addition, the proportion of exchangeable Cd to the total Cd reduced by 10 percentage point after quicklime treatment addition, but the contents of Fe-Mn oxide binding and organic Cd increased. The trends of changes of Cd forms in the other mineral treatments were the same, indicating that the minerals remediate Cd-contaminated soil mainly by the conversion of exchangeable Cd into Fe-Mn oxide binding and organic Cd. Carbonate binding and residue Cd almost did not participate in the process of transformation.

Soil samples were collected from the abandoned Pb-Zn mining area in Huize, Yunnan Province during October of 2020. The dominance degree of the herbaceous plants was evaluated to screen the dominant herbaceous plants suitable for planting in the abandoned mining areas. Soil physical and chemical properties and the heavy metal contents in soil samples were determined. Also, heavy metal contents in the shoots and roots of plants were measured to analyze the accumulation and transportation characteristics of heavy metals in individual or combinations of dominant herbaceous plants. The results show that the soil in the research area is slightly acidic or slightly alkaline. The contents of Mn, Zn, Cd and Pb in soil samples are far exceeding the background value of the area. Cd and Pb are the main pollutants in this area. There are a total of ten dominant herbaceous plants:Setaria viridis, Artemisia lavandulifolia, Cynodon dactylon, Bidens pilosa, Imperata cylindrica, Miscanthus sinensis, Woodwardia japonica, Ageratina adenophora, Chloris virgata and Polygonum hydropiper. Among them, Woodwardia japonica, Polygonum hydropiper and Cynodon dactylon are excellent in the accumulation of Cu, Cd and Pb (bioaccumulation factors between 0.5 and 1.0), and they have a high performance for Mn transportation (transportation factors between 1.0 and 1.5). Therefore, they can be used as a dominant combination for constructing plant communities. Artemisia lavandulifolia and Imperata cylindrica tend to accumulate Cu and Zn in the overground part (bioaccumulation factors between 0.5 and 1.0) and transfer Mn, Cd and Pb in the roots (transportation factors between 1.0 and 1.5). Thus, they can be used as a sub-dominant combination for constructing new plant communities. The other five dominant plants have various performances in heavy metal enrichment and transportation. Among them except for Ageratina adenophora, the other four dominant plants can be used as auxiliary species in new communities. In conclusion, nine dominant herbaceous plants are founded to be suitable for heavy metal pollution treatment and plant diversity restoration. The corresponding plant combinations can be selected according to the type of heavy metal pollution.